Techniques for correction of aberrations

ABSTRACT

Some implementations described herein provide an exposure tool. The exposure tool includes a reticle deformation detector and one or more processors configured to obtain, via the reticle deformation detector, reticle deformation information associated with a reticle during a scanning process for scanning multiple fields of a wafer. The one or more processors determine, based on the reticle deformation information, a deformation of the reticle at multiple times during the scanning process, and perform, based on the deformation of the reticle at the multiple times, one or more adjustments of one or more components of the exposure tool during the scanning process.

CROSS-REFERENCE TO RELATED APPLICATION

This Patent Application claims priority to U.S. Provisional PatentApplication No. 63/200,418, filed on Mar. 5, 2021, and entitled“TECHNIQUES FOR CORRECTION OF ABERRATIONS.” The disclosure of the priorApplication is considered part of and is incorporated by reference intothis Patent Application.

BACKGROUND

Lithography in semiconductor manufacturing (e.g., photolithography) is aprocess of transferring a pattern to a wafer. Lithography may includeapplying light through a reticle (e.g., a photomask) and onto fields ofthe wafer. The reticle is an apparatus that is configured with a pattern(e.g., a die layer pattern, an integrated circuit pattern, among otherexamples) that is transferred to the wafer during the lithographyprocess. The reticle may include a lithography mask on which a patternis formed, a frame to which the lithography mask or reticle is attached,and a pellicle layer to protect the pattern from damage and dust thatcould otherwise cause defects in the transfer of the pattern to thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a diagram of an example of an exposure tool described herein.

FIG. 2 is a diagram of an example of a deformation of a reticledescribed in connection with the exposure tool of FIG. 1.

FIG. 3 is a diagram of an example of a wafer described in connectionwith the exposure tool of FIG. 1.

FIG. 4 is a diagram of an example of correcting aberrations describedherein for use with the exposure tool of FIG. 1.

FIG. 5 is a diagram of an example of a portion of an exposure tooldescribed in connection with the exposure tool of FIG. 1.

FIG. 6 is a diagram of an example of a portion of an exposure tooldescribed in connection with the exposure tool of FIG. 1.

FIG. 7 is a diagram of an example of an exposure tool described inconnection with the exposure tool of FIG. 1.

FIG. 8 is a diagram of example components of one or more devices of FIG.1.

FIG. 9 is a flowchart of an example process relating to correction ofaberrations.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

An exposure tool (e.g., an immersion exposure tool) may be used toperform lithography on the wafer. The exposure tool may operate invarious exposure modes, such as a step exposure mode, a scan exposuremode, or a step-and-scan exposure mode. The exposure tool may include awafer stage that may include a chuck, a platform, or another type ofstructure configured to support and secure the wafer. The wafer stagemay be configured to provide various motions, such as transitionalmotion and/or rotational motion to support the various types of exposuremodes. The wafer may include a plurality of fields having integratedcircuits defined therein for one or more dies. A field includes one ormore circuit dies and a frame region at a boundary area. During alithography scanning process (e.g., an exposure operation), thesubstrate may be scanned (e.g., exposed to light) one field at a time.For example, the exposure tool may scan a pattern of the reticle totransfer the pattern to one field, and may then step to a next field(e.g., by moving the wafer stage) and may repeat the scanning until allfields of the substrate are exhausted.

During a lithography scanning process (e.g., an exposure operation), areticle may change temperature. For example, during the scanningprocess, the reticle may change temperature based on being exposed tolight (e.g., deep ultraviolet (DUV) light or extreme ultraviolet (EUV)light, among other examples). When the reticle is exposed to the light(e.g., the light passes through, is reflected by, or is absorbed by thereticle), the reticle absorbs energy from the light and converts theenergy to heat. In a lithography scanning process that includes scanningseveral fields (e.g., 5 or more fields) of a wafer, a temperature of thereticle may vary dramatically between scans of the several fields and/orduring scans of the several fields. For example, the reticle may have alowest temperature before beginning to scan a first field and may have ahighest temperature during a final portion of a scan of a last field.Additionally, or alternatively, the temperature of the reticle mayfluctuate based on amounts of time between scans, during which time thereticle may cool. Based on the reticle changing temperature, the reticlemay deform, which may cause aberrations in a pattern transferred fromthe reticle onto the wafer. The aberrations (e.g., differences between apattern of the reticle before scanning and the pattern transferred tothe wafer) may cause manufacturing errors and/or may limit widthreduction of structures within the substrate (e.g., based on limitedlithography accuracy).

Some aspects described herein provide techniques and apparatuses for acorrection of aberrations. In some implementations, an exposure tool maydetermine a deformation of a reticle, using a reticle deformationdetector, during a scanning process (e.g., in real time). In someimplementations, the reticle deformation detector may obtain reticledeformation information (e.g., deformation metrics and/or reticletemperatures) associated with the reticle during the scanning process(e.g., during a scan of a field of a wafer and/or between scans ofdifferent fields of a wafer, among other examples). The deformationmetrics may include measurements of temperatures of the reticle duringthe scanning process and/or direct measurements of a real-time shape ofthe reticle during the scanning process, among other examples.

The exposure tool may perform one or more adjustments (e.g., to one ormore components of the exposure tool) based on the deformation of thereticle. In some implementations, the one or more adjustments may bemade during a scan of a field of a wafer (e.g., at a beginning of thescan) and/or between scans of fields of the wafer, among other examples.The one or more adjustments may include, for example, an adjustment to aposition of a projection lens, an amount of time between scans of fieldsof the wafer, and/or orientations of one or more components (e.g.,optical components) of the exposure tool. The one or more adjustmentsmay be configured to reduce or eliminate an aberration that is caused bythe deformation of the reticle. In this way, the exposure tool may beused to form structures having a reduced processing window based on, forexample, having reduced dimensions (e.g., in a lateral direction). Thismay allow for the exposure tool to be used to form devices on the waferwith an improved device density.

FIG. 1 is a diagram of an example of an exposure tool 100 describedherein. The exposure tool 100 includes a scanning component 102 (e.g.,an illumination top module) that includes one or more optical elements104. For example, the one or more optical elements 104 include one ormore mirrors, one or more lenses, one or more apertures (e.g., aperturesthat refract light and/or function as a lens), and/or one or morefilters, among other examples. The scanning component may include acylinder-shaped portion for receiving light that is traveling in alateral direction, and the one or more optical elements 104 may beconfigured to reflect the received light into a vertical direction. Forexample, a mirror of the one or more optical elements 104 may bepositioned with a downward tilt at approximately 45 degrees from thelateral direction to reflect the light in a downward direction.

The exposure tool 100 includes a reticle deformation detector 106. Thereticle deformation detector 106 may be disposed within the scanningcomponent 102, adjacent to an optical element 104 of the one or moreoptical elements 104, and/or along a path that the scanning component102 directs light toward the reticle. In some implementations, thereticle deformation detector 106 is stationary along the path that thescanning component 102 directs light toward the reticle. Alternatively,the reticle deformation detector 106 may be movable, such that thereticle deformation detector 106 may be moved to a detecting position(e.g., to a position with line of sight to the reticle 110 through anopening of the scanning component 102) to obtain deformation metrics(e.g., a reticle temperature and/or measurements of a shape of thereticle 110) and to an inactive position when not obtaining thedeformation metrics. In some implementations, the reticle deformationdetector 106 includes one or more components (e.g., sensors) that areconfigured to obtain measurements of deformation metrics associated witha reticle that is loaded into the exposure tool 100. The reticledeformation detector 106 is configured to obtain deformation metricsassociated with scans of different fields of a wafer (e.g., wafer 118)during the scanning process. The deformation metrics may indicate adeformation of the reticle directly (e.g., via an indication of a shapeand/or size of the reticle) or indirectly (e.g., via a temperature ofthe reticle that can be mapped to the deformation of the reticle).

The exposure tool 100 includes a reticle housing 108 that is configuredto receive a reticle 110. The reticle housing 108 is configured toposition the reticle 110 between the scanning component 102 and aprojection lens housing 112. The projection lens housing 112 may bycylinder-shaped or another shape based on a shape of a projection lens114 disposed within the projection lens housing 112. The exposure tool100 includes a projection lens 114 that is configured to be adjustedwithin the projection lens housing 112. The projection lens 114 may beconfigured to be adjusted during the scanning process based on thedeformation metrics associated with the scans of the different fields ofthe wafer during the scanning process. For example, an activation device116 may move the projection lens 114 (e.g., vertically) to increase ordecrease a distance between the projection lens 114 and the reticle 110and/or the projection lens 114 may be rotated and/or laterally offset tomodify a focus of light that enters the projection lens 114 from thereticle 110. The movement of the projection lens may be limited based ona length of the projection lens housing 112 (e.g., in a direction thatis substantially aligned with a scanning direction of the scanningcomponent 102) and/or a capability of the activation device 116.

The exposure tool 100 may be used to perform a scanning process (e.g.,an exposure operation) to transfer a pattern of the reticle 110 onto awafer 118. The scanning component 102 may receive light from a lightsource. The light may be configured to react with (e.g., cure) aphotoresist material disposed on the wafer 118. The scanning component102 and/or the optical elements 104 direct the light through the reticle110 and toward the wafer 118 during a scan of a field of the wafer 118.The reticle 110 blocks a first portion of the light and passes a secondportion of the light toward the field of the wafer 118 in a patterneddesign. A portion of the photoresist material that is exposed to thesecond portion of the light may cure in a way that causes the portion ofthe photoresist material to react differently from a remaining portionof the photoresist material when a developing agent is applied to thephotoresist material. For example, portions of a positive photoresistmaterial are configured to be removed by the developing agent if theportions of the positive photoresist material have been exposed to thesecond portion of the light. Alternatively, portions of a negativephotoresist material are configured to resist removal by the developingagent if the portions of the negative photoresist material have beenexposed to the second portion of the light. After portions of thephotoresist material have been removed, an etching tool may apply anetching agent (e.g., a liquid or a plasma, among other examples) toremove portions of the wafer that are not insulated by the photoresistmaterial.

Accuracy of filtering the light by the reticle 110 may affect dimensionsof structures that the exposure tool 100 may be used to form withinfields of the wafer 118. Deformation of the reticle during use (e.g.,during a scanning process) may cause aberrations in a pattern of thelight that passes through the reticle 110. The reticle 110 may deformduring the scanning process based on reflecting and/or absorbing photonsof the first portion of the light, which may cause the reticle 110 toincrease in temperature. The increase in temperature may cause thereticle 110 to deform in one or more dimensions based on thermalexpansion of material of the reticle 110.

The reticle deformation detector 106 may obtain deformation metricsassociated with the reticle 110 during the scanning process. In someimplementations, the reticle deformation detector 106 obtains thedeformation metrics at multiple times during the scanning process forscanning multiple fields of a wafer. The reticle deformation detector106 may obtain (e.g., measure) the deformation metrics during scans offields of the wafer (e.g., during each field of the wafer and/or at abeginning of the scans of the fields of the wafer) and/or between scansof the multiple fields of the wafer (e.g., between each scan of eachfield and/or before beginning scans of the multiple fields, among otherexamples). In some implementations, the reticle deformation detector 106may obtain the deformation metrics at a time that is closer to abeginning of a scan of a field than to a completion of a previous scanof a previous field.

Based on the deformation metrics, the exposure tool 100 determines adeformation of the reticle 110 at multiple times during the scanningprocess. In some implementations, the exposure tool 100 determineswhether to adjust one or more components of the exposure tool 100 (e.g.,to adjust the projection lens 114 and/or to replace the reticle 110 witha replacement reticle that has a lower amount of deformation, amongother examples) based on the deformation of the reticle 110. Forexample, the exposure tool 100 may determine to adjust the one or morecomponents based on the deformation metrics and/or the deformation ofthe reticle 110 satisfying a threshold (e.g., a threshold differencefrom a previous set of deformation metrics and/or a previous deformationof the reticle). In some implementations, the exposure tool 100 performsone or more adjustments of one or more components of the exposure tool100 based on the deformation of the reticle 110 and/or the one or moredeformation metrics. In some implementations, the exposure tool 100(e.g., via one or more processors of the exposure tool 100) may performone or more adjustments of one or more components of the exposure tool100 during the scanning process. The exposure tool 100 may perform theone or more adjustments at multiple times during the scanning process(e.g., based on the deformation metrics and/or a deformation of thereticle 110 satisfying a threshold). For example, the exposure tool 100may perform the one or more adjustments of the one or more components ofthe exposure tool 100 between a first scan of a first field of the wafer118 and a second scan of a second field of the wafer 118, or perform theone or more adjustments of the one or more components of the exposuretool 100 during the first scan of the first field of the wafer 118,among other examples. In some implementations, the one or moreadjustments of the one or more components of the exposure tool 100 areconfigured to reduce or eliminate an aberration that would have beencaused by the deformation of the reticle 110 without the one or moreadjustments.

In some implementations, the reticle housing 108 may receive the reticle110 via a reticle handler 120 that stores a set of reticles includingthe reticle 110 and a set of replacement reticles 122. The reticlehandler 120 may be configured to provide the reticle 110 based onreceiving a command from one or more processors of the exposure tool 100or from another device. In some implementations, the reticle handler 120may be configured to replace the reticle 110 with a replacement reticlebased on a deformation of the reticle 110 during a scanning process. Forexample, the exposure tool 100 may determine (e.g., via the reticledeformation detector 106) that the deformation of the reticle 110satisfies a threshold, and may replace the reticle 110 with thereplacement reticle 122 based on a determination that a deformation ofthe replacement reticle 122 is less than the deformation of the reticle110 and/or satisfies a deformation threshold. In some implementations,the replacement reticle 122 may have a deformation that is less than thereticle 110 based on the replacement reticle 122 avoiding, or havingreduced, absorption of energy from light used for the scanning processfor a period of time.

As indicated above, FIG. 1 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 1.

FIG. 2 is a diagram of an example 200 of a deformation of a reticle 110described in connection with the exposure tool of FIG. 1. The reticle110 may be configured with a pattern of material that blocks a firstportion of light that is directed to the reticle 110 in a firstdirection (e.g., a direction that is generally orthogonal to a surfaceof the reticle 110 that includes the pattern) and passes a secondportion of the light that is directed to the reticle 110 in the firstdirection. The pattern may be associated with one or more fields of awafer to which the pattern is to be transferred (e.g., for an etchingoperation).

As shown by reference number 202, the reticle 110 may be exposed tolight (e.g., electromagnetic waves) from one more directions. Forexample, the reticle 110 may be exposed to light at a top surface of thereticle 110 via the scanning component 102 and/or the one or moreoptical elements 104, as described herein. In some implementations, thereticle 110 may be exposed to light at one or more side surfaces of thereticle 110.

As shown by reference number 204, the reticle 110 may deform via thermalexpansion in one or more lateral directions (e.g., an X-direction and/ora Y-direction, among other examples). In some implementations, a reticlehousing (e.g., reticle housing 108) may restrict expansion in the one ormore lateral directions, which may cause an increase of expansion of thereticle 110 in another direction.

As shown by reference number 206, the reticle 110 may deform, viathermal expansion, in a vertical direction. In some implementations,first portions (e.g., a middle portion) of the reticle 110 may expand byan amount that is greater than expansion of second portions (e.g., outerportions) of the reticle 110. In this way, apertures that form thepattern of the reticle 110 may be curved, may be non-parallel, and/ormay not be parallel to a flow of light waves from scanning component 102to the projection lens 114. The deformation of the reticle 110 may causean aberration to a pattern transferred to the wafer 118 without one ormore adjustments to the one or more components of the exposure tool 100during the scanning process. The deformation of the reticle 110 maychange between scans of different fields of the wafer, which may causeaberrations to persist without one or more adjustments to the one ormore components of the exposure tool 100 during and/or between scans ofthe scanning process for scanning the different fields of the wafer.

As indicated above, FIG. 2 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 2.

FIG. 3 is a diagram of an example 300 of a wafer 118 described inconnection with the exposure tool of FIG. 1. As shown in example 300,the wafer 118 may be configured with multiple fields 302 (e.g., 92fields). In some implementations, the fields 302 may be logical fieldsand/or may not be physically delineated portions of the wafer 118 duringone or more operations of a manufacturing process. In someimplementations, a manufacturing process includes performing a scanningprocess to scan multiple fields 302 of the wafer 118. In someimplementations, the manufacturing process includes scanning fewer thanall of the multiple fields 302 of the wafer 118. During a scanningprocess, the reticle may cool between scans of consecutive fields andmay heat during scans of the multiple fields. In some implementations,an amount of cooling may be different between consecutive scans basedon, for example, an amount of time between the consecutive scans (e.g.,based on an amount of time needed for an exposure tool to move betweenfields associated with the consecutive scans), a temperature of thereticle between the consecutive scans (e.g., when at a high temperature,the reticle may cool more quickly), or a temperature of the exposuretool (e.g., when the exposure tool is at a high temperature, the reticlemay cool more slowly), among other examples.

In some implementations, the manufacturing process includes scanning afirst set of the multiple fields 302 of the wafer 118 using a firstreticle and scanning a second set of the multiple fields 302 of thewafer 118 using a second reticle. In some implementations, the first setof the multiple fields 302 may be intended to have a same first patterntransferred thereon and the second set of the multiple fields 302 may beintended to have a same second pattern transferred thereon, where thefirst pattern is different from the second pattern. Based on determiningdeformation of the reticle 110 and correcting for the deformation of thereticle 110 at multiple times during the scanning process, the exposuretool 100 may improve a uniformity of the first set of the multiplefields 302 and a uniformity of the second set of the multiple fields302.

As indicated above, FIG. 3 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 3.

FIG. 4 is a diagram of an example 400 of correcting aberrationsdescribed herein for use with the exposure tool 100 of FIG. 1. Theexposure tool 100 may perform the correction of the aberrations, asdescribed herein. In some implementations, the exposure tool 100 isconfigured with a reticle deformation detector 106 (e.g., a reticletemperature sensor), as described above.

As shown by reference number 402, the exposure tool 100 may receive amapping of reticle temperatures (e.g., temperatures of the reticle 110)to aberration profiles. The mapping may indicate an amount of aberration(e.g., a blurring and/or error of a pattern of a reticle whentransferred to a field of a wafer 118) and/or may be associated with oneor more adjustments to one or more components of the exposure tool 100to correct for an associated deformation of the reticle 110 that isexpected to be caused by the reticle temperatures.

The exposure tool 100 may perform a scan 404 (e.g., an exposure) of afirst field of the wafer 118. During the scan 404 of the first fieldand/or after the scan 404 of the first field, the exposure tool 100measures a reticle temperature 406 associated with the reticle 110. Theexposure tool 100 calculates an aberration drift 408 based on themeasurement of the reticle temperature 406. The aberration drift 408 mayindicate a change of an aberration that would be caused by thedeformation of the reticle 110 without one or more adjustments to one ormore components of the exposure tool 100. The aberration drift 408 mayindicate an amount of additional adjustment that may be made by theexposure tool 100 to correct for a change of the aberration thatoccurred during the scan 404 of the first field.

The exposure tool 100 may perform a scan 410 (e.g., an exposure) of asecond field of the wafer 118. During the scan 410 of the second fieldand/or after the scan 410 of the second field, the exposure tool 100measures a reticle temperature 412 associated with the reticle 110. Theexposure tool 100 calculates an aberration drift 414 based on themeasurement of the reticle temperature 412. The aberration drift 414 mayindicate an amount of additional adjustment that may be made by theexposure tool 100 to correct for a change of the aberration thatoccurred during the scan 410 of the second field.

The exposure tool 100 may perform a scan 416 (e.g., an exposure) of athird field of the wafer 118. During the scan 416 of the third fieldand/or after the scan 416 of the third field, the exposure tool 100measures a reticle temperature 418 associated with the reticle 110. Theexposure tool 100 calculates an aberration drift 420 based on themeasurement of the reticle temperature 418. The aberration drift 420 mayindicate an amount of additional adjustment that may be made by theexposure tool 100 to correct for a change of the aberration thatoccurred during the scan 416 of the third field.

In some implementations, the exposure tool 100 continues scanning fieldsof the wafer 118, measuring reticle temperatures during and/or betweenscans of the fields of the wafer 118, and/or calculating aberrationdrifts associated with the deformation metrics. In some implementations,the exposure tool 100 performs one or more adjustments to one or morecomponents of the exposure tool 100 during the scanning process (e.g.,during scans and/or between scans) based on the aberration drifts, asdescribed herein.

As indicated above, FIG. 4 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 4.

FIG. 5 is a diagram of an example 500 of a portion of an exposure tooldescribed in connection with the exposure tool 100 of FIG. 1. As shownby example 500, the reticle deformation detector 106 may include areticle temperature sensor 106A configured to measure 502 a temperatureof a reticle 110 during a scanning process. The reticle temperaturesensor 106A may include, for example, a non-contact thermometer.

In some implementations, the temperature of the reticle 110 isassociated with a deformation of the reticle 110. The exposure tool 100may estimate the deformation of the reticle 110 based on the temperatureof the reticle 110 during the scanning process.

In some implementations, the reticle temperature sensor 106A ispositioned on, or adjacent to, the scanning component 102 that isconfigured to direct light through the reticle 110 and toward the wafer118. For example, the reticle temperature sensor 106A may be disposedon, or adjacent to, an optical element 104 of the scanning component102. Additionally, or alternatively, the reticle temperature sensor 106Amay be substantially aligned with a scanning direction of the scanningcomponent 102 (e.g., a direction of a flow of light toward the wafer118).

The exposure tool 100 may determine an aberration drift based ontemperatures of the reticle 110 as measured by the reticle temperaturesensor 106A. The aberration drift may indicate a change of an aberration(e.g., based on the deformation of the reticle) that has occurred sincea previous measurement and/or since a previous adjustment to the one ormore components of the exposure tool 100. The exposure tool 100determines one or more modifications to apply to the one or morecomponents of the exposure tool 100 to compensate for the aberrationdrift.

As indicated above, FIG. 5 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 5.

FIG. 6 is a diagram of an example 600 of correcting aberrationsdescribed herein for use with the exposure tool 100 of FIG. 1. Theexposure tool 100 may perform the correction of the aberrations, asdescribed herein. In some implementations, the exposure tool 100 isconfigured with a reticle deformation detector 106 (e.g., anelectromagnetic wave-based scanner), as described above.

As shown by reference number 602, the exposure tool 100 may receive amapping of deformation metrics (e.g., scans of s surface of the reticle110) to aberration profiles. The mapping may indicate an amount ofaberration (e.g., a blurring and/or error of a pattern of a reticle whentransferred to a field of a wafer 118) and/or may be associated with oneor more adjustments to one or more components of the exposure tool 100to correct for an associated deformation of the reticle 110 that isexpected to be caused by the deformation metrics.

The exposure tool 100 may perform a scan 604 (e.g., an exposure) of afirst field of the wafer 118. During the scan 604 of the first fieldand/or after the scan 604 of the first field, the exposure tool 100obtains deformation metrics 606 associated with the reticle 110. Theexposure tool 100 calculates an aberration drift 608 based on thedeformation metrics 606. The aberration drift 608 may indicate a changeof an aberration that would be caused by the deformation of the reticle110 without one or more adjustments to one or more components of theexposure tool 100. The aberration drift 608 may indicate an amount ofadditional adjustment that may be made by the exposure tool 100 tocorrect for a change of the aberration that occurred during the scan 604of the first field.

The exposure tool 100 may perform a scan 610 (e.g., an exposure) of asecond field of the wafer 118. During the scan 610 of the second fieldand/or after the scan 610 of the second field, the exposure tool 100obtains deformation metrics 612 associated with the reticle 110. Theexposure tool 100 calculates an aberration drift 614 based on thedeformation metrics 612. The aberration drift 614 may indicate an amountof additional adjustment that may be made by the exposure tool 100 tocorrect for a change of the aberration that occurred during the scan 610of the second field.

The exposure tool 100 may perform a scan 616 (e.g., an exposure) of athird field of the wafer 118. During the scan 616 of the third fieldand/or after the scan 610 of the third field, the exposure tool 100obtains deformation metrics 618 associated with the reticle 110. Theexposure tool 100 calculates an aberration drift 620 based on themeasurement of the deformation metrics 618. The aberration drift 620 mayindicate an amount of additional adjustment that may be made by theexposure tool 100 to correct for a change of the aberration thatoccurred during the scan 616 of the third field.

In some implementations, the exposure tool 100 continues scanning fieldsof the wafer 118, obtaining deformation metrics during and/or betweenscans of the fields of the wafer 118, and/or calculating aberrationdrifts associated with the deformation metrics. In some implementations,the exposure tool 100 performs one or more adjustments to one or morecomponents of the exposure tool 100 during the scanning process (e.g.,during scans and/or between scans) based on the aberration drifts, asdescribed herein.

As indicated above, FIG. 6 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 6.

FIG. 7 is a diagram of an example 700 of a portion of an exposure tooldescribed in connection with the exposure tool of FIG. 1. As shown byexample 700, the reticle deformation detector 106 may include anelectromagnetic wave-based scanner 106B configured to measure adeformation of a reticle 110 during a scanning process. Theelectromagnetic wave-based scanner 106B may include, for example, alaser and a sensor. In some implementations, the laser is configured toemit light at a surface of the reticle 110 and the sensor is configuredto measure optical path lengths 702 of light that reflects off of thereticle 110. In some implementations, the electromagnetic wave-basedscanner 106B includes multiple lasers and/or multiple sensors to measurethe deformation of the reticle 110 during the scanning process.

The exposure tool 100 may determine thicknesses of one or more portionsof the reticle 110 during the scanning process based on the optical pathlengths 702. The exposure tool 100 may determine the deformation of thereticle 110 based on the thicknesses of the one or more portions of thereticle. For example, the exposure tool 100 may determine (e.g.,estimate) the deformation of the reticle 110 based on a thickness of acenter portion of the reticle 110. Additionally, or alternatively, theexposure tool 100 may determine the deformation of the reticle 110 basedon thicknesses of the reticle 110 at multiple locations. In this way,the exposure tool 100 may determine an asymmetrical deformation of thereticle 110. Based on determining an asymmetrical deformation of thereticle 110, the exposure tool 100 may improve correction of thedeformation based on applying one or more adjustments of one or morecomponents of the exposure tool 100 (e.g., rotation of the projectionlens 114, and/or offsetting of the projection lens housing 112 relativeto the field, among other examples).

In some implementations, the electromagnetic wave-based scanner 106B ispositioned on, or adjacent to, the scanning component 102 that isconfigured to direct light through the reticle 110 and toward the wafer118. For example, the electromagnetic wave-based scanner 106B may bedisposed on, or adjacent to, an optical element 104 of the scanningcomponent 102. Additionally, or alternatively, the electromagneticwave-based scanner 106B may be substantially aligned with a scanningdirection of the scanning component 102 (e.g., a direction of a flow oflight toward the wafer 118).

The electromagnetic wave-based scanner 106B may measure optical pathlengths once or multiple times during a scan of a field of the wafer118. Multiple measurements may improve a deformation determinationand/or correction of aberrations; however, each measurement of opticalpaths via the electromagnetic wave-based scanner 106B may increasedeformation of the reticle (e.g., based on absorbing energy from thelaser).

The exposure tool 100 may determine an aberration drift based on thedeformation of the reticle 110 as measured by the electromagneticwave-based scanner 106B. The aberration drift may indicate change of anaberration (e.g., based on the deformation of the reticle) that hasoccurred since a previous measurement and/or since a previous adjustmentto the one or more components of the exposure tool 100. The exposuretool 100 determines one or more modifications to apply to the one ormore components of the exposure tool 100 to compensate for theaberration drift.

As indicated above, FIG. 7 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 7.

FIG. 8 is a diagram of example components of a device 800, which maycorrespond to exposure tool 100. In some implementations, the exposuretool 100 may include one or more devices 800 and/or one or morecomponents of device 800. As shown in FIG. 8, device 800 may include abus 810, a processor 820, a memory 830, a storage component 840, aninput component 850, an output component 860, and a communicationcomponent 870.

Bus 810 includes a component that enables wired and/or wirelesscommunication among the components of device 800. Processor 820 includesa central processing unit, a graphics processing unit, a microprocessor,a controller, a microcontroller, a digital signal processor, afield-programmable gate array, an application-specific integratedcircuit, and/or another type of processing component. Processor 820 isimplemented in hardware, firmware, or a combination of hardware andsoftware. In some implementations, processor 820 includes one or moreprocessors capable of being programmed to perform a function. Memory 830includes a random access memory, a read only memory, and/or another typeof memory (e.g., a flash memory, a magnetic memory, and/or an opticalmemory).

Storage component 840 stores information and/or software related to theoperation of device 800. For example, storage component 840 may includea hard disk drive, a magnetic disk drive, an optical disk drive, a solidstate disk drive, a compact disc, a digital versatile disc, and/oranother type of non-transitory computer-readable medium. Input component850 enables device 800 to receive input, such as user input and/orsensed inputs. For example, input component 850 may include a touchscreen, a keyboard, a keypad, a mouse, a button, a microphone, a switch,a sensor, a global positioning system component, an accelerometer, agyroscope, and/or an actuator. Output component 860 enables device 800to provide output, such as via a display, a speaker, and/or one or morelight-emitting diodes. Communication component 870 enables device 800 tocommunicate with other devices, such as via a wired connection and/or awireless connection. For example, communication component 870 mayinclude a receiver, a transmitter, a transceiver, a modem, a networkinterface card, and/or an antenna.

Device 800 may perform one or more processes described herein. Forexample, a non-transitory computer-readable medium (e.g., memory 830and/or storage component 840) may store a set of instructions (e.g., oneor more instructions, code, software code, and/or program code) forexecution by processor 820. Processor 820 may execute the set ofinstructions to perform one or more processes described herein. In someimplementations, execution of the set of instructions, by one or moreprocessors 820, causes the one or more processors 820 and/or the device800 to perform one or more processes described herein. In someimplementations, hardwired circuitry may be used instead of or incombination with the instructions to perform one or more processesdescribed herein. Thus, implementations described herein are not limitedto any specific combination of hardware circuitry and software.

The number and arrangement of components shown in FIG. 8 are provided asan example. Device 800 may include additional components, fewercomponents, different components, or differently arranged componentsthan those shown in FIG. 8. Additionally, or alternatively, a set ofcomponents (e.g., one or more components) of device 800 may perform oneor more functions described as being performed by another set ofcomponents of device 800.

FIG. 9 is a flowchart of an example process 900 relating to correctionof aberrations. In some implementations, one or more process blocks ofFIG. 9 may be performed by an exposure tool (e.g., exposure tool 100).Additionally, or alternatively, one or more process blocks of FIG. 9 maybe performed by one or more components of device 800, such as processor820, memory 830, storage component 840, input component 850, outputcomponent 860, and/or communication component 870.

As shown in FIG. 9, process 900 may include performing a first scan of afirst field of a wafer (block 910). For example, the exposure tool 100may perform a first scan of a first field 302 of a wafer 118, the firstscan including projecting an electromagnetic field through a reticle 110and onto the first field 302 of the wafer 118, as described above.

As further shown in FIG. 9, process 900 may include obtaining reticledeformation information associated with deformation of the reticle 110during the first scan (block 920). For example, the exposure tool 100may obtain deformation metrics associated with deformation of thereticle 110 during the first scan, as described above.

As further shown in FIG. 9, process 900 may include performing, based onthe reticle deformation information, one or more adjustments of one ormore components of the exposure tool (block 930). For example, theexposure tool 100 may perform, based on the deformation metrics, one ormore adjustments of one or more components 108, 112, 114 of the exposuretool 100, as described above.

As further shown in FIG. 9, process 900 may include performing, afterperforming the one or more adjustments of the one or more components ofthe exposure tool, a second scan of a second field of the wafer, thesecond scan including projecting the electromagnetic field through thereticle and onto the second field of the wafer (block 940). For example,the exposure tool 100 may perform, after performing the one or moreadjustments of the one or more components of the exposure tool 100, asecond scan of a second field 302 of the wafer 118, the second scanincluding projecting the electromagnetic field through the reticle 110and onto the second field 302 of the wafer 118, as described above.

Process 900 may include additional implementations, such as any singleimplementation or any combination of implementations described belowand/or in connection with one or more other processes describedelsewhere herein.

In a first implementation, performing the one or more adjustments of theone or more components of the exposure tool comprises one or more ofadjusting the one or more components 108, 112, 114 of the exposure tool100 during the first scan, adjusting the one or more components 108,112, 114 of the exposure tool 100 before the second scan, or adjustingthe one or more components 108, 112, 114 of the exposure tool 100 duringthe second scan.

In a second implementation, alone or in combination with the firstimplementation, obtaining the reticle deformation information comprisesdetecting a temperature of the reticle 110 during the first scan, ormeasuring the deformation of the reticle 110 using an electromagneticwave-based scanner 106B.

In a third implementation, alone or in combination with one or more ofthe first and second implementations, process 900 includes obtaining, bythe reticle deformation detector 106, additional reticle deformationinformation associated with the deformation of the reticle 110 duringthe second scan, and performing, based on the additional reticledeformation information, one or more adjustments of one or morecomponents 108, 112, 114 of the exposure tool 100.

In a fourth implementation, alone or in combination with one or more ofthe first through third implementations, performing the one or moreadjustments of the one or more components 108, 112, 114 of the exposuretool 100 comprises one or more of replacing the reticle 110 with areplacement reticle 110 based on the deformation of the reticle 110, oradjusting a projection lens 114 of the exposure tool 100.

Although FIG. 9 shows example blocks of process 900, in someimplementations, process 900 may include additional blocks, fewerblocks, different blocks, or differently arranged blocks than thosedepicted in FIG. 9. Additionally, or alternatively, two or more of theblocks of process 900 may be performed in parallel.

Based on determining a deformation of a reticle during a scanningprocess for scanning multiple fields of a wafer (e.g., instead ofdetermining a deformation of the reticle only after scanning all fieldsof a wafer and before an additional scanning process for scanningmultiple fields of a subsequent wafer), and making one or moreadjustments of one or more components of an exposure tool during thescanning process, the exposure tool may reduce aberrations that wouldotherwise be caused by the deformation of the reticle. In this way, theexposure tool may be used to form structures having a reduced processingwindow based on, for example, having reduced dimensions (e.g., in alateral direction). This may allow for the exposure tool to be used toform devices on the wafer with an improved device density.

As described in greater detail above, some implementations describedherein provide an exposure tool. The exposure tool includes a reticledeformation detector and one or more processors configured, obtain, viathe reticle deformation detector, reticle deformation informationassociated with a reticle, at multiple instances during a scanningprocess that includes scanning multiple fields of a wafer. The one ormore processors determine, based on the reticle deformation information,a deformation of the reticle at multiple instances during the scanningprocess, and perform, based on the deformation of the reticle at themultiple instances, one or more adjustments of one or more components ofthe exposure tool at multiple times during the scanning process.

As described in greater detail above, some implementations describedherein provide a method. The method includes performing, by an exposuretool, a first scan of a first field of a wafer, where the first scanincludes projecting an electromagnetic field through a reticle and ontothe first field of the wafer. The method includes obtaining, by areticle deformation detector, reticle deformation information associatedwith deformation of the reticle during the first scan. The methodincludes performing, based on the reticle deformation information, oneor more adjustments of one or more components of the exposure tool. Themethod includes performing, by the exposure tool and after performingthe one or more adjustments of the one or more components of theexposure tool, a second scan of a second field of the wafer, where thesecond scan includes projecting the electromagnetic field through thereticle and onto the second field of the wafer.

As described in greater detail above, some implementations describedherein provide an exposure tool. The exposure tool includes a scanningcomponent configured to perform a scanning process that comprisesdirecting light through a reticle and toward a wafer. The exposure toolincludes a reticle deformation detector configured to obtain reticledeformation information, at multiple instances of the scanning process,associated with scans of different fields of the wafer during thescanning process. The exposure tool includes a projection lens that isconfigured to be adjusted during the scanning process based on thereticle deformation information associated with the scans of thedifferent fields of the wafer during the scanning process. The exposuretool includes a reticle housing configured to position the reticlebetween the scanning component and the projection lens.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. An exposure tool comprising: a reticledeformation detector; and one or more processors configured to: obtain,via the reticle deformation detector, reticle deformation information,associated with a reticle, at multiple instances during a scanningprocess that includes scanning multiple fields of a wafer, determine,based on the reticle deformation information, a deformation of thereticle at multiple instances during the scanning process, and perform,based on the deformation of the reticle at the multiple instances, oneor more adjustments of one or more components of the exposure tool atmultiple times during the scanning process.
 2. The exposure tool ofclaim 1, wherein the one or more adjustments of the one or morecomponents of the exposure tool are configured to reduce or eliminate anaberration that would have been caused by the deformation of the reticlewithout the one or more adjustments.
 3. The exposure tool of claim 1,wherein the one or more processors, to perform the one or moreadjustments of the one or more components of the exposure tool, areconfigured to cause one or more of: the reticle to be replaced with areplacement reticle based on the deformation of the reticle, or aprojection lens of the exposure tool to be adjusted.
 4. The exposuretool of claim 1, wherein the one or more processors, to perform the oneor more adjustments of the one or more components of the exposure tool,are configured to: perform the one or more adjustments of the one ormore components of the exposure tool between a first scan of a firstfield of the wafer and a second scan of a second field of the wafer, orperform the one or more adjustments of the one or more components of theexposure tool during the first scan of the first field of the wafer. 5.The exposure tool of claim 1, wherein the reticle deformation detectorcomprises a reticle temperature sensor configured to measure atemperature of the reticle during the scanning process.
 6. The exposuretool of claim 5, wherein the one or more processors are configured to:estimate the deformation of the reticle based on the temperature of thereticle during the scanning process.
 7. The exposure tool of claim 5,wherein the one or more processors are configured to determine anaberration drift based on a mapping of measured temperatures of thereticle to aberrations of the scanning process, and wherein the one ormore processors, to perform the one or more adjustments of the one ormore components of the exposure tool during the scanning process, areconfigured to: perform the one or more adjustments of the one or morecomponents of the exposure tool during the scanning process based on theaberration drift.
 8. The exposure tool of claim 5, wherein the reticletemperature sensor is positioned on, or adjacent to, a scanningcomponent configured to direct light through the reticle and toward thewafer, and wherein the reticle temperature sensor is substantiallyaligned with a scanning direction of the scanning component.
 9. Theexposure tool of claim 5, wherein the reticle temperature sensorcomprises: a non-contact thermometer.
 10. The exposure tool of claim 1,wherein the reticle deformation detector comprises an electromagneticwave-based scanner configured to measure the deformation of the reticle.11. The exposure tool of claim 10, wherein the electromagneticwave-based scanner comprises a laser and a sensor, wherein the laser isconfigured to emit light at a surface of the reticle, wherein the sensoris configured to measure optical path lengths of light that reflects offof the reticle, and wherein the one or more processors, to determine thedeformation of the reticle, are configured to determine thicknesses ofone or more portions of the reticle during the scanning process based onthe optical path lengths of the light that reflects off of the reticle.12. The exposure tool of claim 11, wherein the one or more processorsare configured to: determine an aberration drift based on thethicknesses of the one or more portions of the reticle, and determineone or more modifications to apply to the one or more components of theexposure tool to compensate for the aberration drift.
 13. A method,comprising: performing, by an exposure tool, a first scan of a firstfield of a wafer, the first scan including projecting an electromagneticfield through a reticle and onto the first field of the wafer;obtaining, by a reticle deformation detector, reticle deformationinformation associated with deformation of the reticle during the firstscan; performing, based on the reticle deformation information, one ormore adjustments of one or more components of the exposure tool; andperforming, by the exposure tool and after performing the one or moreadjustments of the one or more components of the exposure tool, a secondscan of a second field of the wafer, the second scan includingprojecting the electromagnetic field through the reticle and onto thesecond field of the wafer.
 14. The method of claim 13, whereinperforming the one or more adjustments of the one or more components ofthe exposure tool comprises one or more of: adjusting the one or morecomponents of the exposure tool during the first scan, adjusting the oneor more components of the exposure tool before the second scan, oradjusting the one or more components of the exposure tool during thesecond scan.
 15. The method of claim 13, wherein obtaining the reticledeformation information comprises: detecting a temperature of thereticle during the first scan, or measuring the deformation of thereticle using an electromagnetic wave-based scanner.
 16. The method ofclaim 13, further comprising: obtaining, by the reticle deformationdetector, additional reticle deformation information associated with thedeformation of the reticle during the second scan; and performing, basedon the additional reticle deformation information, one or moreadjustments of one or more components of the exposure tool.
 17. Themethod of claim 13, wherein performing the one or more adjustments ofthe one or more components of the exposure tool comprises one or moreof: replacing the reticle with a replacement reticle based on thedeformation of the reticle, or adjusting a projection lens of theexposure tool.
 18. An exposure tool comprising: a scanning componentconfigured to perform a scanning process that comprises directing lightthrough a reticle and toward a wafer; a reticle deformation detectorconfigured to obtain reticle deformation information, at multipleinstances of the scanning process, associated with scans of differentfields of the wafer during the scanning process; a projection lens thatis configured to be adjusted during the scanning process based on thereticle deformation information associated with the scans of thedifferent fields of the wafer during the scanning process; and a reticlehousing configured to position the reticle between the scanningcomponent and the projection lens.
 19. The exposure tool of claim 18,wherein the reticle deformation detector comprises: a reticletemperature sensor, or an electromagnetic wave-based scanner.
 20. Theexposure tool of claim 18, further comprising the reticle disposed inthe reticle housing.